n 1999 the National Center for Biotechnology Information (NCBI) at the National Library of Medicine (NLM) released PubRef in response to a request made by the National Academy of Sciences and a number of publishers. PubRef was designed as a service to expand the bibliographic linking feature in PubMed and facilitate linking to a broader set of scientific journals outside of biomedicine and full-text of articles at publishers' web sites. PubRef consists of about 90,000 citations from the Physical Reviews Series, plus about 10,000 records from ten other journals.

In early 2001 PubRef will be discontinued. This decision was made because the number of PubRef searches have been negligible, and also an independent service, CrossRef was developed whose purpose is quite similar to PubRef.

PubRef, will therefore, be removed from the Subset list on PubMed's Limit screen. Also,"AND notpubref[sb]" will no longer appear on the Details screen which shows how PubMed has translated your search.

The former PubRef citations will be added to PubMed, but will not receive MEDLINE indexing unless the journals are submitted to LSTRC for review and recommendation for inclusion in MEDLINE.